An electromechanically operated motor vehicle brake having an actuator is known in principle and comprises an electric motor that is controlled by an electronic control unit (ECU). The vehicle brake has an actuating element (brake piston) that acts upon at least one friction lining and can be displaced from a rest position into an actuation position, in which the actuating element applies the friction lining against a friction ring. The actuating element (brake piston) can be operated by an electric motor-gearbox unit. The friction lining can thereby be applied to a friction ring in a regulated manner.
Actuators in motor vehicles, especially actuators for operating motor vehicle brakes, are subjected to very different stresses and operating temperatures. In order to always be able to safely park the vehicle, a defined application force is to be provided which can be performed by a specified, defined application of current to the actuator during control or regulation of the actuator taking into account current operating parameters.
A method for controlling an electrically operated parking brake is known from DE 103 61 042 B3, which is incorporated herein by reference. With this method, the switch-off current of the electric motor is varied to compensate for aging-related and wear-related changes of the application force or changes of the application force because of changes of the resistance and/or the temperature of the electric motor or a loss of efficiency. There is a criticism that in principle the method described above causes a loss of actuator efficiency, while increased power demands are made on other vehicle systems (on-board electrical system).